Revert 251206 "Fixes crashes wrt to the maximize button when:"

trunk/src/ash/wm/caption_buttons/frame_maximize_button.h

Index: trunk/src/ash/wm/caption_buttons/frame_maximize_button.h
===================================================================
--- trunk/src/ash/wm/caption_buttons/frame_maximize_button.h	(revision 251215)
+++ trunk/src/ash/wm/caption_buttons/frame_maximize_button.h	(working copy)
@@ -8,7 +8,6 @@
 #include "ash/ash_export.h"
 #include "ash/wm/caption_buttons/caption_button_types.h"
 #include "ash/wm/caption_buttons/frame_caption_button.h"
-#include "ash/wm/window_state_observer.h"
 #include "ash/wm/workspace/snap_types.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/observer_list.h"
@@ -33,8 +32,7 @@
 // Button used for the maximize control on the frame. Handles snapping logic.
 class ASH_EXPORT FrameMaximizeButton : public FrameCaptionButton,
                                        public views::WidgetObserver,
-                                       public aura::WindowObserver,
-                                       public wm::WindowStateObserver {
+                                       public aura::WindowObserver {
  public:
   FrameMaximizeButton(views::ButtonListener* listener,
                       views::Widget* frame);
@@ -69,10 +67,6 @@
                                        intptr_t old) OVERRIDE;
   virtual void OnWindowDestroying(aura::Window* window) OVERRIDE;
 
-  // wm::WindowStateObserver override:
-  virtual void OnWindowShowTypeChanged(wm::WindowState* window_state,
-                                       wm::WindowShowType old_type) OVERRIDE;
-
   // WidgetObserver overrides:
   virtual void OnWidgetActivationChanged(views::Widget* widget,
                                         bool active) OVERRIDE;